Odds and ends...
I know a way I found by accident. Reach under the passenger seat and unplug the plug (the only one, it goes to the seat belt tensioner I think).
Disclaimer: I don't know exactly what this does but you will get an airbag light on the dash, which will go out when you replugged and restart van. I'm not sure if it stores codes, but I was told it does disable that airbag. I wouldn't think it would disable both, but as I said, I don't know for sure. Hopefully someone will. I'd like to know too.
Currently vanless. Weird.